/***
 * ASM Guide
 * Copyright (c) 2007 Eric Bruneton, 2011 Google
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

package cn.zwy.tree.day2;

import static org.objectweb.asm.Opcodes.ACC_PRIVATE;
import static org.objectweb.asm.Opcodes.ACC_PUBLIC;
import static org.objectweb.asm.Opcodes.ALOAD;
import static org.objectweb.asm.Opcodes.ATHROW;
import static org.objectweb.asm.Opcodes.DUP;
import static org.objectweb.asm.Opcodes.F_SAME;
import static org.objectweb.asm.Opcodes.GETFIELD;
import static org.objectweb.asm.Opcodes.GOTO;
import static org.objectweb.asm.Opcodes.IFLT;
import static org.objectweb.asm.Opcodes.ILOAD;
import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
import static org.objectweb.asm.Opcodes.IRETURN;
import static org.objectweb.asm.Opcodes.NEW;
import static org.objectweb.asm.Opcodes.PUTFIELD;
import static org.objectweb.asm.Opcodes.RETURN;
import static org.objectweb.asm.Opcodes.V1_6;

import java.io.PrintWriter;

import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.FieldInsnNode;
import org.objectweb.asm.tree.FieldNode;
import org.objectweb.asm.tree.FrameNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.InsnNode;
import org.objectweb.asm.tree.JumpInsnNode;
import org.objectweb.asm.tree.LabelNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.TypeInsnNode;
import org.objectweb.asm.tree.VarInsnNode;

/**
 * ASM Guide example class.
 * 
 * @author Eric Bruneton
 */
public class BeanGenerator {

    public byte[] generate(PrintWriter printWriter) {
        ClassNode cn = new ClassNode();
        cn.version = V1_6;
        cn.access = ACC_PUBLIC;
        cn.name = "pkg/Bean";
        cn.superName = "java/lang/Object";
        cn.sourceDebug = "Bean.java";
        cn.fields.add(new FieldNode(ACC_PRIVATE, "f", "I", null, null));
        {
            MethodNode mn = new MethodNode(ACC_PUBLIC, "<init>", "()V", null, null);
            cn.methods.add(mn);
            InsnList il = mn.instructions;
            il.add(new VarInsnNode(ALOAD, 0));
            il.add(new MethodInsnNode(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false));
            il.add(new InsnNode(RETURN));
            mn.maxStack = 1;
            mn.maxLocals = 1;
        }
        {
            MethodNode mn = new MethodNode(ACC_PUBLIC, "getF", "()I", null, null);
            cn.methods.add(mn);
            InsnList il = mn.instructions;
            il.add(new VarInsnNode(ALOAD, 0));
            il.add(new FieldInsnNode(GETFIELD, "pkg/Bean", "f", "I"));
            il.add(new InsnNode(IRETURN));
            mn.maxStack = 1;
            mn.maxLocals = 1;
        }
        {
            MethodNode mn = new MethodNode(ACC_PUBLIC, "setF", "(I)V", null, null);
            cn.methods.add(mn);
            InsnList il = mn.instructions;
            il.add(new VarInsnNode(ALOAD, 0));
            il.add(new VarInsnNode(ILOAD, 1));
            il.add(new FieldInsnNode(PUTFIELD, "pkg/Bean", "f", "I"));
            il.add(new InsnNode(RETURN));
            mn.maxStack = 2;
            mn.maxLocals = 2;
        }
        MethodNode mn = new MethodNode(ACC_PUBLIC, "checkAndSetF", "(I)V", null, null);
        cn.methods.add(mn);
        InsnList il = mn.instructions;
        il.add(new VarInsnNode(ILOAD, 1));
        LabelNode label = new LabelNode();
        il.add(new JumpInsnNode(IFLT, label));
        il.add(new VarInsnNode(ALOAD, 0));
        il.add(new VarInsnNode(ILOAD, 1));
        il.add(new FieldInsnNode(PUTFIELD, "pkg/Bean", "f", "I"));
        LabelNode end = new LabelNode();
        il.add(new JumpInsnNode(GOTO, end));
        il.add(label);
        il.add(new FrameNode(F_SAME, 0, null, 0, null));
        il.add(new TypeInsnNode(NEW, "java/lang/IllegalArgumentException"));
        il.add(new InsnNode(DUP));
        il.add(new MethodInsnNode(INVOKESPECIAL, "java/lang/IllegalArgumentException", "<init>", "()V", false));
        il.add(new InsnNode(ATHROW));
        il.add(end);
        il.add(new FrameNode(F_SAME, 0, null, 0, null));
        il.add(new InsnNode(RETURN));
        mn.maxStack = 2;
        mn.maxLocals = 2;
        ClassWriter cw = new ClassWriter(0);
        cn.accept(cw);
        return cw.toByteArray();
    }
}
